if a == 13 or a == 14 or a == 17 or a == 18 or a == 19:
    a = 0
  if b == 13 or b == 14 or b == 17 or b == 18 or b == 19:
    b = 0
  if c == 13 or c == 14 or c == 17 or c == 18 or c == 19:
    c = 0
  return (a + b + c)